Time delay estimation is a signal processing technique that is used to estimate the time delay between two signals obtained from two different sensors that are physically displaced. For example, a microphone array includes a set of microphones spaced at particular distances from each other. Because sound does not travel instantaneously, a sound emanating from a source will reach some microphones before reaching others. Thus, the signal received by a microphone farther away from the source will be delayed from the signal received by a microphone that is closer to the source.
The signals received by each of the microphones can be analyzed to determine this time delay. Knowing the time delay can be useful for a variety of applications including source localization and beamforming. The time delay is often estimated using a process referred to as a Generalized Cross-Correlation Phase Transform (GCC-PHAT). This method performs satisfactorily with low and moderate levels of background noise. However, this method does not do well with larger levels of background noise or moderate reverberation.
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